This invention relates to an electronic musical instrument with a keyboard and, more particularly, to an electronic musical instrument which can provide musical tones with glide effect.
A tone generated by an electronic musical instrument and having a glide effect, sounds like a tone generated by a brass instrument. The pitch of any musical tone produced by brass instruments gradually and slightly falls or rises to the proper pitch of the tone. How fast and in which direction the pitch changes depends on the manner in which the player plays the instrument, and also on the pitch of the preceding or succeeding tone.
Musical tones with a glide effect are generated by the conventional electronic musical instrument with a keyboard in the following manner. First, the player turns on a switch, whereby the instrument becomes able to produce tones with glide effect. When the player depresses any key of the keyboard, a tone signal is generated. The frequency of this signal gradually falls or rises to the frequency corresponding to the proper pitch of the musical tone to which the key is assigned. A loudspeaker converts this signal into a musical tone which sounds like one generated by brass instruments.
In the case of the conventional electronic musical instrument, the glide period, which elapses until the frequency of a tone signal falls or rises to the value corresponding to the proper pitch of the musical tone, is constant. Also constant is the difference between the initial frequency of the signal and the frequency corresponding to the proper pitch of the tone. Neither the glide period nor the frequency difference for every tone with glide effect is changed, no matter how quickly and how strongly the player depresses the key. Consequently, the musical instrument cannot generate musical tones with a delicate glide effect, and the player cannot make a sophisticated musical expression when he or she plays this instrument.